Hydraulic tappet oil reservoir control



P 7, 1954 J. w. HUMPHREYS HYDRAULIC TAPPET OIL RESERVOIR CONTROL Filed Aug. 14, 1953 INVENTOR.

HUMPHREYS (JOHN W.

ATTORN EY Patented Sept. 7, 1954 HYDRAULIC TAPPET OIL RESERVOIR CONTROL John W. Humphreys, Muskegon, Mich., assignor to Johnson Products, Inc., Muskegon, Mich., a corporation of Michigan Application August 14, 1953, Serial No. 374,214

This invention relates to a practical, useful and very simple and inexpensive oil reservoir control for hydraulic tappets used in internal combustion engines. Such invention, for its utility, is applied to hydraulic tappets which are located with a longitudinal axis inclined to the vertical instead of being located vertically as in the straight type of internal combustion engine. Engines known as V-engines, that is, with two banks of cylinders at opposite sides of a central vertical plane, inclined downwardly and inwardly toward each other and toward such central vertical plane, have the tappets located at approximately the same angle as the axes of said cylinders. Such tappets of hydraulic type inthe V-engines have had the defect, at times, of losing oil in the oil compression chambers or reservoirs of the tappets, which permits air to enter such chambers, this occurring while the engine is at rest and not operating. Thereupon, upon starting the engine, it takes a period of time before such air can be worked out of the tappet, with accompanying deficiency in operation of the engine and the production of tappet noises over quite considerable periods of time, until all air has 'been purged from the compression chamber.

It is an object and purpose of the present invention to cure this defect, which may not come into play with each stopping of an engine, but which occurs with sufiicient frequency to be annoying in addition to whatever damaging effects upon engine valves may result from such air entrance into the pressure chambers of hydraulic tappets.

An understanding of the invention may be had from the following description taken in connection with the accompanying drawing, in which,

Figs. 1, 2, 3 and 4 are respectively, a perspective View, a perspective view in reverse, a. plan view and a central vertical section through the control member which, with my invention, is added to a regular hydraulic tappet, and

Fig. 5 is a central vertical section through a tappet equipped with my invention, the tappet being in a position inclined to the vertical.

Like reference characters refer to like parts in the different figures of the drawing.

The tappet structure, furnishing the environment in which my invention is used, includes the usual tappet body I interiorly bored from one end toward but short of the other end, in which a tappet piston 2 is received, movable lengthwise of and within the tappet body and below which, at the lower end portion of the tappet body is a chamber 3 in which oil, the hydraulic liquid used,

4 Claims. (01. 123-90) is held and which is automatically. supplied in engine operation to properly maintain valve opening and closing.

The piston 2 is hollow, open at its upper end and has a closed lower end except for a central outlet passage 4 therethrough. A valve and spring holding cage 5, within which is a valve 6, spring actuated by a light coiled spring 1 to normally hold the valve 6 against the lower end of a piston 2 around the opening t is well known structure in tappets, a relatively heavy coiled compression spring 9 being within thechamber 3 and engaging the cage 5 to hold it against the bottom of the piston 2 and tending to force the piston in an upward direction.

The wall of the piston 2 has one or more transverse openings Ifi therethrough adjacent the lower end of a closure I l at the upper end of the piston 2, which is recessed at its upper side to receive the lower end of a push rod or valve stem. The closure member ll enters the upper end of the piston 2 until stopped by an annular flange at its upper end as shown.

With my invention, the upper end portion of the piston 2 is interiorly enlarged in diameter by a reaming or other cutting and finishing operation to a point below the openings Ill, leaving a continuous annular shoulder [2. Into the upper end portion of the piston the oil control member of my invention is inserted and pressed into place, having a tight, snug fit. It comprises a transverse member of an inverted dish or shallow cup form, made of thin sheet metal, having a top I3 with sides around it extending downwardly and outwardly and terminating'in a downwardly extending annular flange I4, the lower edges of which rest upon the annular shoulder at l2. The top l3 of said member has a central opening l5 therethrough and is also supplied around the opening with a plurality of spaced upwardly extending dimples 16 which, when the assembly of the tappet is complete, at their upper ends bear against the lower end of the member I l as shown in Fig. 5.

In the normal operation of the engine, oil through the usual conduits therefor from the lubricant supply of the engine, passes through the walls of the tappet body I in a plane closely approximating the plane of the openings II] of the walls of the piston 2, oil being supplied to pass to the interior of the piston through the openings Hi. It is from this reservoir of oil that the chamber 3 is supplied in engine operation by oil going through the passage 4 and past the valve 6 into the chamber 3,

When an engine having hydraulic tappets is running, all of the tappets are full of oil, and all air is absent from them. When the engine is stopped, atmospheric pressure forces oil from the tappets and the oil lines, draining it back to the crankcase. Oil in the tappets is drained out through the hole Hi and through the opening in the tappet body, whereupon, as a worst condition, the oil within the piston 2 left is that indicated in dash and dot lines at I! with the sheet metal member l4 not in place. By adding and using the sheet metal member, oil can drain only to the horizontal plane of the lowest side of opening [5 so that the oil in the tappet reservoir within the piston is increased to the amount shown in the short dashed lines at 18.

Such difference in oil level is important when the engine is started, especially in connection with those tappets on the cams which are stopped in an up position. In such position the engine valves are held open whereupon the valve springs force the tappet pistons down to lowermost position, that is, the lower end of piston 2 comes against the shoulder at the upper end of chamber 3. Oil is forced from the chamber 3 by such action and must be immediately replaced during the first revolution of the camshaft when the engine is again started if a loud clicking tappet noise is to be avoided.

When the engine is started during the first revolution of the camshaft, as soon as an engine valve which has been held up reaches its closed position, spring ii moves the piston 2 upwardly and oil from the reservoir of the piston 2 flows into the chamber 3. indicated at I! such oil at ll is reduced in volume so that the passage 4 may be uncovered and air get into the compression chamber 3, but with the oil level increased by the additional amount indicated at l8 such air passing condition through the passage 4 will not occur. Without the member l4 and with the oil level as it is shown at H,

With the oil level at that air many times is drawn into the chamber 3 when the piston is forced upwardly by spring a on starting an engine, and air admitted to the chamber 3, compressing every time the tappet is raised by the cam causes the objectionable tappet noise. Such noise will continue because with the close fit of the piston 2 in the bore of the body I, past which piston the air must escape, several minutes are required to get out the air and stop such noise.

The upwardly pressed separated dimples I6 provide a passage for oil through the openings 10 into the piston 2 by flowing to and through the opening l5 and thence into the piston below the control member which has been described. Such dimples IS in practice may be in substantial contact with the lower end of the closure at l l at the upper end of the tappet piston.

The pressed metal cup member i4 is slightly larger in diameter than the interior diameter of the piston 2 into which it is forced. This provides a tight fit between the periphery of the flanges l4 and the reamed bore of piston 2 in which they fit, preventing leakage of oil between the parts. It is important that there be no leakage past the flanges M in order to maintain the oil level in the reservoir to that indicated at I8, and one of the features of this invention is to prevent such leakage.

The structure described is very economical to produce as an additional improvement to tappets, being particularly useful in conjunction with socalled V-engines, the number of which is greatly increasing in the motor vehicle field. Its manufacture and assembly adds little to the manufacturing cost of production of the tappet. It operates as an insurance against the previous undesired entrance of air into the tappet, particularly to the lower end oil pressure chamber 3 thereof.

The invention is defined in the appended claims and is to be considered comprehensive of all forms of structure coming within their scope.

I claim:

1. In a hollow piston for a hydraulic tappet, said piston having an opening through a side thereof for entrance of liquid to the interior of said piston and a normally valve closed outlet at its lower end below said entrance opening, the improvement comprising, a transverse partition within said piston having a generally central opening therethrough, said partition being located in the piston between said entrance and outlet openings thereof.

2. In a hollow piston for a hydraulic tappet, said piston having a transverse opening through a side thereof toward its upper end and 2, normally valve closed axial opening through its lower end, the improvement comprising, a generally transverse partition across the interior of said piston between said openings therein located adjacent the first mentioned opening, said partition having a generally central opening therethrough.

3. In a hollow piston for a hydraulic tappet, said piston having a transverse opening through a side thereof toward its upper end and an axial opening through its lower end normally valve closed, the improvement comprising, an annular shoulder at the interior of said piston below the first mentioned opening, and a partition of thin metal located transversely of and within said piston, bearing at its peripheral edges against said shoulder, said partition having a generally central opening therethrough.

4. In a hollow piston for a hydraulic tappet, said piston having a transverse opening through a side thereof toward its upper end and an axial opening through its lower end, normally closed by a spring actuated valve, and a closure for the upper end of said piston, the improvement comprising, av continuous annular shoulder at the interior of said piston adjacent and below said first mentioned opening, and a partition of thin metal located across and within said piston having a continuous annular peripheral flange bearing against said shoulder, said partition having a generally central opening therethrough, and having spaced upwardly extending projections around said opening .against which the inner end of said closure is adapted to bear.

No references cited. 

